Hooks error related to exclamation points

[veloper]

/Users/user/.rvm/gems/ruby-1.9.3-p448@sourcing_r3211/gems/hooks-0.2.2/lib/hooks/inheritable_attribute.rb:30:in `instance_eval': (eval):3: syntax error, unexpected '!', expecting keyword_end (SyntaxError)
          @_after_start!_callbacks = v
                        ^
(eval):7: syntax error, unexpected '!', expecting keyword_end
...          return @_after_start!_callbacks unless superclass....
...                               ^
(eval):7: syntax error, unexpected tIDENTIFIER, expecting ')'
...nd_to?(:_after_start!_callbacks) and value = superclass._aft...
...                               ^
(eval):8: syntax error, unexpected '!', expecting keyword_end
          @_after_start!_callbacks ||= value.clone # ...

[veloper]

hooks-0.3.3 is now a requirement.